Compounded oil



PatentedFeb. 24,1942

COMPOUNDED OIL Lloyd 11. Mulit, Richmond, Calif., assignor to StandardOil Company of California, San Francisco, Calif., a corporation ofDelaware No Drawing. Application January 22, 1940, Serial No. 315,035

20 Claims.

This invention relates to a new and useful composition of matter andinvolves a composition comprising a hydrocarbon'oil and a newcombination of stabilizing ingredients. More particularly; the inventionpertains to a viscous hydrocarbon oil containing a metal alcoholate anda salt of a substituted acid of phosphorus.

The production of improved hydrocarbon oils, and particularly oflubricating oils having desired characteristics, has been the subject ofextensive research. Generally speaking, the compounding of hydrocarbonoils to obtain desired characteristics involves empirical phenomena andthe action of untested combinations of different types of compoundingagents cannot be predicted.

A characteristic which has been th subject of extensive investigation isthe tendency of hydrocarbon oils to deteriorate or partially decomposeand oxidize when subjected to high temperatures. This deterioration isevidenced by the deposition of adhesive deposits on hot metal surfacesover which the hydrocarbon oil may flow. It is important that resistanceto such deterioration be imparted to hydrocarbon'oils, particularly tolubricating oils, in order that such compositions may be relatively freefrom the tendency to form such deposits even under high temperatures andsevere operating conditions. A direct result of this type ofdeterioration during lubrication of internal combustion engines is theformation of varnish on the pistons and cylinder walls, and in enginesof the Diesel type a pronounced tendency of the oil to cause or permitthe sticking of piston rings.

The crankcase lubricant in internal combustion engines is subjected toextremely severe operating conditions, and in engines of the Diesel typethe lubricant encounters in the piston ring zone temperatures of fromapproximately 425 to 650 F. and pressures from the oxidizing combustiongases as high as 750 to 1150 pounds per square inch. In its morespecific aspects the present invention is directed to the improvement ofhydrocarbon lubricating oils by imparting thereto increased resistanceto deterioration by heat at high temperature levels in the order ofthose abovementioned. It has been discovered that salts of substitutedacids of phosphorus containing an organic substituent in combinationwith metal alcoholates impart to hydrocarbon lubricating oils a numberof highly desirable properties and improve the lubrication and operationof internal combustion engines. More particularly, it has beendiscovered that a lubricating oil containing both a metal alcoholate anda salt of an organic substituted acid of phosphorus permits longerperiods of operation of engines without the necessity of major overhaulsheretofore occasioned by stuck piston rings, wear of pistons andcylinder walls, or in some instances corrosion of bearing metal alloys.

The broader aspects of the invention involve the discovery that salts ofsubstituted acids of phosphorus containing an organic substituent andmetal alcoholates cooperate to give new results in hydrocarbon oilcompositions. Hydrocarbon oils containing this combination ofingredients have greater stability under various operating conditionsthan do oils containing either of these types of ingredients alone. Forexample, the same improvement is not obtainable with 0.75% of a metalalcoholate or with 0.75% of such salts in a lubricating oil as isobtained with 0.50% of the metal alcoholate and 0.25% of the same saltin the same lubricating oil. The mechanism of this cooperation has notbeen established and the inventor therefore refrains from any attemptedexplanation of the phenomena observed.

It should be noted that oxidation inhibitors or antioxidants which areeffective at low temperatures to inhibit oxidation in hydrocarbon oilsmay not be efiective at higher temperatures and under more severeoperating conditions, such as those which lubricating oils encounter inthe piston ring belt of internal combustion engines such as Dieselengines. Although the broader aspects of the invention are not solimited, it is preferred to utilize in combination with metal alcoholates salts of substituted acids of phosphorus containing organicsubstituents efiective above 300 F., and preferably effective to inhibitoxidation of lubricating oils containing metal alcoholates attemperatures in the range of 400 to 500 F.

Metal alcoholates which may be added to hydrocarbon oils, such asmineral lubricating oils, to

provide one component of the new composition of matter herein claimedcomprise the alkali, al-

kaline earth, aluminum, and other heavy metal alcoholates. Examples ofsuch alcoholates are: sodium alcoholates, potassium alcoholates,beryllium alcoholates; calcium alcoholates, strontium alcoholates,barium alcoholates, magnesium alcoholates, zinc alcoholates, cadmiumalcoholates, and aluminum alcoholates.

Metal alcoholates which may be utilized and which fall within the scopeof this invention are represented by the type formula:

where M represents a metal, X indicates oxygen or sulfur, C anon-benzenoid carbon atom, R an organic radical of hydrocarbonstructure, and n is from one to the valence of the metal. M is a metalsuch as those previously listed. By nonbenzenoid carbon atom it isintended to designate a carbon atom which is not in the nucleus of abenzene ring, although attachment to a henzene ring is not precluded.Examples of radicals of hydrocarbon structure which R represents are:alkyl, aryi, alkaryl, aralkyl and cyclic nonbenzenoid.- R need notnecessarily be a pure hydrocarbon radical but may contain othersubstituents, such as oxygen, halogens, nitrogens, and the like. Acyclicradicals are preferred, and the entire compound preferably contains atleast ten carbon atoms.

Examples of preferred alcohols utilized to form the metal alcoholate arethe higher alcohols, such as amyl, hexyl, heptyl, octyl, nonyl, decyl(lauryl), dodecyl, tetradecyl, hex-adeoyl (cetyl), octadecyl, ceryl,myricyl, and unsaturated alcohols, such as lanolin alcohol. Thefollowing are metal alcoholates of these alcohols which are embraced bythis invention: sodium amylate, sodium hexylate, sodium heptylate,sodium octylate, sodium nonylate, sodium decylate, sodium dodecylate,sodium tetradecylate, sodium hexadecylate, sodium octadecylate, sodiumcerylate, sodium myricylate, sodium lanoiate (sodium salt of lanolinalcohol), calcium amylate, calcium hexylate, calcium heptylate, calciumoctylate, calcium nonylate, calcium decylate, calcium dodecylate,calcium tetradecylate, calcium hexadecylate, calcium octadecylate,calcium cerylate, calcium myricylate, calcium lanolate (calcium salt oflanolin alcohol), magnesium amylate, magnesium hexylate, magnesiumhepylate, magnesium oetylate, magnesium nonylate, magnesium decylate,magnesium dodecylate, magnesium tetradecylate, magnesium hexadecylate,magnesium octadecylate, magnesium eerylate, magnesium myricyiate,magnesium lanolate (magnesium salt of lanolin alcohol) barium amylate,barium .nexylate, barium heptylate, barium octylate, barium nonylate,barium decylate, barium dodecylate, barium tetradecylate, bariumhexadecylate, barium octadecylatabarium cerylate, barium myricylate,barium lanolate (barium salt of lanolin alcohol), aluminum amylate,aluminum hexylate, aluminum heptylate, aluminum octylate, aluminumnonylate, aluminum decylate, aluminum dodecylate, aluminumtetradecylate, aluminum hexadecylate, aluminum octadecylate, aluminumcerylate, aluminum myricylate, and aluminum lanolate (aluminum salt oflanolin alcohol).

Additional alcohols are: cyclo-alkyl alcohols like cyclohexanol, andaralkyl alcohols like benzyl alcohol, .as well as acyclic thioalcohols,cyclo-alkyl thioalcohols, and arakyl thioalcohols, in which sulfurreplaces the normal oxygen of the alcoholic group. Examples ofthioalcohols are the mercaptans, such as amyl mercaptan, hexylmercaptans, cyclohexyl mercaptans and the like. Metal derivatives oforganic compounds capable of forming the enolic structure also may beutilized. Such derivatives of the enolic compounds contain the grouprepresented by the type formula:

where R representsan organic radical, preferably a hydrocarbon group,and M represents a bond to a metal atom. I

The metal alcoholates of this invention may be prepared by any suitablemethod. For example, sodium' alcoholates may be prepared by reactionwith sodium metal, the calcium alcobarium holates by reaction of thealcohol with calcium carbide, and the aluminum alcoholates by reactionwith metallic aluminum catalyzedwith a crystal of iodine.

Metal salts of substituted acids of phosphorus which may be utilized inthe invention comprise salts of metals selected from Groups I, II, III,IV and VI of Mendeleefi's Periodic Table of the Elements. Specificexamples of such metals are aluminum, calcium, barium, strontium,chromium and magnesium. Salts of iron, cobalt, nickel, zinc, sodium,potassium and ammonium comprise additional examples of compounds fallingwithin the broader aspects of the invention.

Although the broader aspects of the invention are not so limited it ispreferred to utilize in combination with the metal alcoholates heavymetal salts of, substituted acids of phosphorus and, still morespecifically, alkaline earth salts, like calcium salts, of said acids inhydrocarbon lubricating oils.

The following comprise specific examples of metal salts of substitutedacids of phosphorus, illustrating this type of compounding agent:aluminum lauryl phosphate, aluminum cetyl phosphate, aluminum octadecylphosphate, aluminum spermol phosphate, aluminum oleyl phosphate,aluminum spermenyl phosphate,'

aluminum di-(cyclohexanyl) phosphate, aluminum (cetyl phenyl) phosphate,aluminum di- (amylphenyl) phosphate, aluminum di-stearoglycerylphosphate, aluminum (tetra-chlorooctadecyl) phosphate, aluminumdi-(fi-chloro, 2-phenyl phenyl) phosphate, aluminum di- (3-methyl,i-chloro phenyl) phosphate, aluminum naphthenyl phosphate, calciumlauryl phosphate, calcium cetyl phosphate, calcium octadecyl phosphate,calcium spermol phosphate, calcium oleyl phosphate, calcium spermenylphosphate, calcium di-(cyclohexanyl) phosphate, calcium (cetyl phenyl)phosphate, calcium di-(amylphenyl) phosphate, calcium distearo-glycerylphosphate, calcium (tetrachloro-octadecyl) phosphate, calcium di-(6-chloro, Z-phenyl phenyl) phosphate, calcium di- (3-methyl, 4-chlorophenyl) phosphate, calcium naphthenyl phosphate, chromium laurylphosphate, chromium cetyl phosphate, chromium octadecyl phosphate,chromium spermol phosphate, chromium oleyl phosphate, chromium spermenylphosphate, chromium di-(cyclohexan'yl) phosphate, chromium cetyl phenylphosphate, chromium di-.(amylphenyl) phosphate, chromiumdi-stearo-glyceryl phosphate, chromium tetra-chloro-octadecyl phosphate,chromium di-(6-ch1or0, 2-phenyl'phenyl) phos= phate, chromiumdi-(3-methyl, 4-chloro phenyl) phosphate, chromium naphthenyl phosphate,barium lauryl phosphate, barium cetyl phosphate, barium octadecylphosphate, barium spermol phosphate, barium oleyl phosphate,

spermenyl phosphate, barium di- (cyclohexanyl) phosphate, barium cetylphenyl phosphate, barium di-(amylphenyl) phosphate,

barium di-stearo-glyceryl phosphate, barium tetra-chloro-octadecylphosphate, barium di- (G-chloro, 2-phenyl phenyl) phosphate, barium di-(3-methyl, 4-chl'oro phenyl) phosphate, barium naphthenyl phosphate, aswell as corresponding sodium, potassium, magnesium and ammonium salts.

The salts of the substituted acids of phosphorus involved herein arepreferably formed from substituted oxy or sulfur containing acids ofpenadvantage of the phosphates.

tavalent phosphorus of the following type formulaet which may be used informing the metal salts of the present invention are as follows:

OH R-P\ phosphonic acid H OH 0 I R=P mono-cstcr of phosphonic acid I I 0R 0 P-OH phosphinic acid l In all of the above formulae R and R may bealkyl, aryl, alkaryl, aralkyl, or cyclic non-benzenoid groups.

In all of the above formulae for the various acids of phosphorus R andR. need not be pure hydrocarbon constituents but are preferably ofhydrocarbon structure and may comprise oxygenated hydrocarbon radicals,such as alcohols, ketones, esters and ethers, or may be hydrocarbonradicals containing substituted constituents, such as halogens(chlorine, bromine, iodine), amino or nitro substituents. Likewise, R insome instances may be an oil-soluble heterocyclic constituent, such as anitrogen containing organic ring compound.

Hydrocarbon oils containing both a metal a1- coholate and a salt of asubstituted acid of phosphorus have new and unpredictable advantagesillustrated by the following discussion and data:

A lubricating oil containing a metal alcoholate and a salt of asubstituted acid of phosphorus containing an organic substituent is moreefiicient in the lubrication of internal combustion engines than is anoil containing either of the components alone. In engine tests it hasbeen found that metal alcoholates permit the formation of a gum orvarnish on portions of the pistons after prolonged periods of operation.Various of the metal alcoholates have also been found to impartcorrosiveness toward copper-lead or cadmium-silver alloy bearings tolubricating oils containing the same. A phosphate, such as calcium cetylphosphate, overcomes or minimizes these disadvantages; 0n the otherhand, calcium cetyl phosphate permits thermal decomposition of the oiland some deposition of carbon in the top piston ring grooves undersevere operating conditions. The metal alcoholate minimizes this dis-Thus by using these two types of ingredients in combination inlubricating oils, each of which has one or more disadvantages, alubricating oil having none of the above described objections isobtained and both formation of gum or varnish" on the piston skirt anddeposition of carbon in the piston ring grooves, as well as corrosion ofalloy bearings, are prevented or inhibited. The following table givesdata illustrating the enhanced effectiveness of the combination inpreventing piston ring sticking and in inhibiting varnish formationthepiston discoloration number being a measure of varnish formation:

- Pistondiscolnrii- Ring- -2 tion number on sticking g hours 1 its.

perm" 60 hrs. 120 hrs.

Acid refined Western oil S.AlE.30 700 Ditto-{1591; calcium lanolate 25I60 Ditto+.8% calcium cetyl phosphate 0 120 225 Ditto+.5% calciumcetylate+.25% calcium cetyl phosphate 120+ 0 T0 Obtained byextrapolation.

The following table also gives data establishing the non-corrosivenessof the compounded oil toward copper-lead and cadmium-silver bearingmetal alloys, as well as inspections on the used oil showing enhancedstability:

Acid refined Westcm oil S. A. E. 30

Compounding agent 0.5% Ca lsnolate+ None 0.25% Ga cetyl phosphaieCorrosion72 hrs. mg. loss:

Copper-lead 13. 9 G. 6 Cadmium-silver 0. 4 0. 0 Used oil inspection:

Vise. increase SSU 100 F 477 251 Naphthainsoluhle 388 I 35 In the aboveengine tests a single cylinder, 2%" bore and 2 /2 stroke Lauson gasolineengine was operated under extremely severe conditions for the purpose ofdeveloping fully piston ring sticking and piston gumming tendenciesunder circumstances simulating severe operating conditions encounteredin the field. Operation of the motor during tests was continuous at 1600R. P. M. speed with periodic shutdowns at fifteenhour intervals forinspection. The jacket temperature was maintained at 375 F. and the sumpoil temperature at 220 F. In the corrosion tests the following methodwas utilized: Glass tubes 2" in diameter and 20" long were immersed inan oil bath, the temperature of which was automatically controlled towithin 11 F. of the test temperature which was 300 F. Approximately 300cc. of oil under test was placed in each tube and air was bubbledthrough it at the rate of 10 liters per hour. Strips of the two types ofbearing metal were placed in the oil. In most cases the copper-lead andthe cadmium-silver bearing alloys were tested simultaneously in the samesample of oil. The weight loss of each strip was recorded. Beforeweighing, each strip was washed in petroleum ether and carefully dried.The duration of the test was 72 hours.

It has also been discovered that hydrocarbon oils containing aninhibitor comprising a metal salt of a substituted acid of phosphorus,such as lubricating oil is to encounter.

calcium cetyl phosphate, form a black deposit with the compounded oil at300. F. and the temperature gradually raised to 550 F., at which pointit is maintained for one hour. In this test the hot wire is partiallyimmersed and partially exposed in air, and the amount of deposition atthe oil surface is observed. The following data illustrate theimprovements resulting in the above described test: W

i Deposit 011 mm.

Acid refined Western oil S. A. E. 30 0. 8 Ditto+.75% calcium lanolate0.0 Ditto+.75% calcium cetyl phosphate .l 83. 4 Biting-8.5% calciumlanolate+.25% calcium cetyl phos- O p a An additional new resultobtained by the com bination of inhibitors utilized in this inventioncomprises increased stability of the oil solution of each of saidcomponents. Lubricating oils containing the metal phosphates alone maybecome cloudyin storage and the metal salts of substituted acids ofphosphorus tend to precipitate from the oil solution in the presence .ofmoisture. Some metal alcoholates'are subject to precipitation fromsolution in lubricating oils or cloud formation in the presence ofwater. When both the alcoholate and the phosphate are present in thelubricating oil the solution becomes more stable against precipitationor cloud forma-- tion. Thus-the metal alcoholates act as a stabilizingagent for the metal salts of the substituted acids of phosphorus andpermit the preparation of more concentrated solutions of the salts thanmight otherwise be feasible.

The limiting adhesion temperature of the com pounded oil hereindisclosed is also enhanced. The limiting adhesion temperature is thetemperature at the hottest point to which the oil will flow uphill andis a'measure of the ability of the oil to lubricate and spread over hotsurfaces such as the upper portions of the cylinder walls of internalcombustion engines. This temperature may be ascertained by tilting ametal trough at a 1 angle, heating the trough at its lower end only sothat a temperature gradient from the hotter lower end to the coolerupperend of the trough is obtained, placing a drop of oil upon the trough,and determining the temperature at the point to which the oil flows.

From the above detailed descriptions it will be apparent that thecombinations of ingredients herein disclosed give a new compositionhaving new and highly useful properties. It is immabearing metals.

pounded oil may be somewhat corrosive to copper-lead or cadmium-silverbearing metals, Babbitt bearings may belittle if at all affected by suchcorrosive action. Hence, compounded oils which may not be particularlydesirable for lubrication of copper-lead or cadmium-silver bearings athigh temperatures where corrosion becomes a factor of importance may behighly useful and extremely advantageous in conjunction with theoperation of internal combustion engines having bearings of Babbitt orother corrosive-resistant The present invention in its broader aspectsis therefore not limited to the particular combination of ingredientshaving all or the greatest number of advantages but embraces various ofth less advantageou addition agents which will find utility inparticular applications. where all the possible improvements in theproperties may not be required or where the standard of performance maynot be so high.

A moderatelyacid refined naphthenic base lubricating oil is thepreferred base oil stock for the compounded lubricants involved herein.The compounding ingredients appear to functionmore efficiently in such abase oil than in parafflnic oil stocks or highly refined naphthenicoils. However, it is to be understood that the invention is not limitedto any particular base stock since advantages herein disclosed may beobtained, at least to some degree, with various oil stocks, theselection of which will be determined by conditions and service whichthe compounded lubricant is to encounter.

The proportion of the salt of substituted acids of phosphorus containingan organic substituent which may be added to mineral lubricating oilsaccording to the principles of the present invention may vary widelydepending upon the uses involved andthe properties desired. As little as0.05% by weight of the salts gives measurable improvements. Fromapproximately 0.1% to 2% of the compound may be added to lubricantscontaining metal alcoholates where stability at high terial for thepurpose of the present invention whether the separate components be newor old, since it is the discovery of the combination of ingredients andthe unpredictable properties obtained thereby which comprise applicant'scontribution to the art.

The compounded lubricants herein disclosed may have one or moreadvantages depending upon the particular compounds selected, theproportions utilized, and the environment which the It should beobserved, for example, that even though a comtemperature comprises theprincipal property desired. Solutions containing more than 2% of thesalt in mineral oils may be utilized for varisired. As little as 0.1% byweight of the alcoholate gives measurable improvement, although fromapproximately 0.25% to approximately 2% alcoholate is preferred wherethe compounded oil is to be used as a crankcase lubricant for internalcombustion engines. As much as 50% or more by weight of various of thealcoholates may be dissolved in mineral oil for the purpose of preparinga concentrate capable of dilution with lubricating oils and the. like.Concentrates con taining high percentages of the alcoholate and the saltof the substituted acid of phosphorus comprise a convenient method 01handling the ingredients and may be used as addition agents forlubricants in general, as well as for other purposes.

The combination ofingredients of this invention may be present inhydrocarbon oils containing other compounding agents, such as pour pointdepressants, oiliness agents, extreme pres sure addition agents,blooming agents, andcompounds for enhancing the viscosity index of thehydrocarbon oil. The invention in its broader aspects embraces mineralhydrocarbon oils containing, in addition to the metal alcoholate and thesalt of the substituted acid of phosphorus, thickening agents and/ormetal soaps in greaseforming proportions or in amounts insuflicient toform grease, as in the case of mineral castor machine oils or othercompounded liquid lubricants.

While the character of the invention has been described in detail andnumerous examples of the composition given, this has been done by way ofillustration only and with the intention that no limitation should beimposed on the invention thereby. It will be apparent to those skilledin the art that numerous modifications and variations of theillustrative examples may be effected in the practice of the inventionwhich is of the scope of the claims appended hereto.

I claim:

1. A composition comprising a hydrocarbon oil, a small amount of a metalalcoholate sufiicient to stabilize said oil against deterioration atelevated temperatures, and a salt of a substituted acid of phosphoruscontaining an organic substituent, said salt being present in a smallamount sufiicient to minimize the corrosive tendencies of the oilsolution of metal alcoholate.

2. A composition as defined in claim 1, in which said salt is a heavymetal salt of a substituted acid of phosphorus. l

3. A composition as defined in claim 1, in which said salt is analkaline earth metal salt of a substituted acid of phosphorus.

4. A composition as defined in claim 1, in which said salt is a calciumsalt of a substituted acid of phosphorus.

5. A composition as defined in claim 1, in which said salt is a chromiumsalt of a substituted acid of phosphorus.

6. A composition as defined in claim 1, in which said salt is amagnesium salt of a substituted acid of phosphorus.

'7. A composition comprising a hydrocarbon oil, a small amount of ametal alcoholate sufiicient to stabilize said oil against deteriorationat elevated temperatures, and a metal salt of a substituted oxyacid ofpentavalent phosphorus containing an organic substituent, said saltbeing present in a small amount sufilcient to minimize the corrosivetendencies of the oil solution of metal alcoholate.

8. A composition as defined in claim '7, in which said salt is analkaline metal salt of a substituted acid of phosphorus.

9. A composition as defined in claim '7, in which said salt is analkaline earth metal salt of a substituted acid of phosphorus.

10. A composition as defined in claim 7, in which said salt is a calciumsalt of a substituted acid of phosphorus.

11. A composition as defined in claim '7, in which said salt is achromium salt of a substituted acid of phosphorus.

12. A composition as defined in claim '7, in which said salt is amagnesium salt of a substituted acid of phosphorus.

13. A composition of matter comprising a hydrocarbon oil, fromapproximately 0.1% to 2% by weight of a compound of the type formula:

where M is a metal, X is selected from the group consisting of oxygenand sulfur, C is a non-- benzenoid carbon atom, R is an organic radicalof hydrocarbon structure, and n may have a value of from one to thevalence of the metal; and from approximately 0.05% to 2% by weight of asalt of an acid selected from the group consisting of:

wherein R. and R are organic radicals of hydrocarbon structure.

14. A composition as defined in claim 13, in which M is an alkalineearth metal.

15. A composition as defined in claim 13, in which M is calcium and thesalt is a calcium salt.

16. A composition as defined in claim 13, in which the salt is analkaline earth metal salt.

17. A process of stabilizing a hydrocarbon oil subject to deteriorationunder oxidizing conditions and deposition of oil-insoluble adhesivematerials on hot metal surfaces when in contact therewith whichcomprises stabilizing said oil by incorporating a small amount of a saltof an acid of phosphorus containing an organic substituent andaugmenting the stabilizing action of said salt with a small amount of ametal alcoholate in said 011, whereby oxidation and deposition of saidadhesive materials are inhibited.

18. A compounded lubricant comprising a lubricating oil subject todeterioration under oxi dizing conditions and deposition ofoil-insoluble adhesive materials on hot metal surfaces when in contacttherewith and a small amount of a stabilizing agent for inhibiting bothtypes of deterioration comprising a mixture in said oil of a polyvalentmetal salt of a substituted acid of phosphorus containing an organicsubstituent and a metal alcoholate, said metal alcoholate being presentin an amount sufiicient to augment the action of said salt.

19. A compounded lubricant comprising a lubricating oil subject tovarnish formation and piston ring sticking tendencies when used as acrankcase lubricant in internal combustion engines, a small amount of apolyvalent metal salt of a substituted acid of phosphorus containing anorganic substituent insufiicient alone adequately to inhibit bothvarnish formation and piston ring sticking, and a small amount of ametal alcoholate insufficient alone adequately to inhibit both varnishformation and piston ring sticking, said salt being present in an amountof at least about 0.05% by weight based on the oil and said metalalcoholate being present in an amount of at least about 0.1% by weightbased on the oil, the alcoholate and salt cooperating to stabilize saidlubricating oil against both varnish formation and piston ring stickingtendencies.

20. A stabilizer for lubricants comprising a concentrated solution of asalt of an acid of phosphorus containing an organic substituent and anaugmenting agent for said salt consisting of a metal alcoholate, saidsolution being capable of dilution with mineral lubricating oil to forma homogeneous mixture containing from approximately 0.05% to 2% byweight of the salt and from approximately 0.1% to 2% by weight of themetal alcoholate, said percentages being based on the total amount oflubricating oil.

LLOYD H. MULI'I.

